Golf ball and method of manufacturing same



June' 30, 1931. r A. CHRISTIE Y 1, 5 GOLF 341.1, AND MVE-THCD'OF mwumcwnme sms 7' Filed on, 12, 1929 v INVENTOR .I'70H/V A. CHRIS 7v:

* QWQW ATTORNEYS Patented June 30, 1931 301m a. cmusrm, or Ami, onxo ecumr. am) nnrnon or muracrunme em Application filed October 12, 1928. Serial Io. $99,135

This invention relates particularly to the manufacture of golf balls, although some asects of the invention are not necessarily imited to the specific aplication to the game olf. As the manu acture of golf balls is pro ably the field which affords the greatest and most profitable outlet for the invention and its widest use, it will be .described for that purpose. It is to be understood, how 1 ever, that should the invention be a plicable to other fields, such fields are inten ed to be covered herein. The satisfactory olf ball of the present major portion comtime comprises a b y or posed of a thread or ribbon of rubber wound about a small rubber ball constituting a core under considerable tension, and enclosed within an outer tta percha or hard rubber casing. This he has up to the resent time 2 been the only satisfactory ball or the purose, having the advantages of greatest resil; ience and consequently maximum flight. It is, however, expensive to manufacture reuirin special winding machinery to cm t e ru ber bo y and the outer covering is easily cut, thereby rendering the ball unplayable.

. Attempts have been made prior to my in vention to construct substitutes for the standard golf ball, but so far as I am aware, the resultant balls have not been satisfactory as they have not affected in any manner the goinliinating position of the standard wound a tutes a method of manufacturing a ball which is equal in many respects to the standard golfball, and in all other respects is superior thereto. The ball manufactured by the process disclosed isof equal resilience with the standard golf ball, and, therefore, has an equally long flight. It is cheaper to manufacture and will not out under the most severe use. I It is of the same weight for size as the standard golf ball, and gives the same click upon being struck which is recognized as characteristic of. high grade golf balls. It does not get out of round and has the same to characteristics in respect toits behavior on The present invention, however, consti-' the fairway and on thegreens ard ball, 7

Y The best known method of'manufacturin the improved golf ball will bedescribed, re erence being had to the accompanying draw ings. It will be understood that while the description able one s improved article, sarily be varied or modified within the S00 invention as set forth herein and in t appended hereto.

In the drawings:

Figure 1 is a view showing the first step in the process, whi h comprises the milling and 1shepting of the compound entering into the Figure 2 is a plan lled in the art to manufacture the e claims of a portion of one of the sheets illustrating the composition of the sheet e t Stands Even herein is detailed so as to en-.

such details need not necesbe followed in every respect, but may of the Figure 3 is a view showing the next step in the process, which is the formation of a roll made from the sheet of Figures 1 and 2;

Figure 4 shows the dividing of the roll into individual masses or pellets for the making of individual balls;

igure 5 shows the mass or pellets of Fig -I ure 4 in position in the mold; 4

Figure 6 is a view showing the ball within the mold, the mold being shown in section;

and

with fibrous material. fillers, curing agents and a rapid accelerator so that the resultant Figure 7 is a cross-sectlon through. the fin-' product has the desirable qualities of weight,-,i

'livelinessand toughness. For the rubber ingredient suitable raw rubber,

smoked sheets are used, although oth'ergrades of rubber standard upon the market may be employed. With this rubber is compounded a suitable quantity of filleror pigment, preferably china clay, although other fillers may be employed to give the ball its proper density and specific gravity. To assist in the vulcanization and also to provide additional preferably filler, zinc oxide or equivalent mineral substances may be employed.

To the rubber so compounded is added a suitable quantity of fibrous material, preferably cotton fibre, although silk fibre, wool, leather or asbestos may be used. Cotton fibre is preferred for its many desirable properties known to those skilled in this art.

Sulphur for vulcanization is also added together with an accelerator of the organic type which is used for obtaining a rapid vulcanization at high temperature. Many forms of accelerators are known and have been developed for this purpose. I have employed with success small portions of tetramethyl-thiuram disulphide and di-orthotolyl-guanidine.

As an example merely, of a successful compound for the purpose, the following will suffice Parts Smoked sheets 76 Zinc oxide 13 China clay 15 Cotton fibres 38 Sulphur Tetra-methyl-thiuram disulphide 1 Di-ortho-tolyl-guanidine 1 These ingredients or any suitable substitute and equivalent thereof, are mixed in any suitable manner known to the trade. care being taken to avoid premature vulcanization owing to the presence of the powerful accelerating ingredients. The mass of rubber compounding ingredients is shown at 1 and is mixed and sheeted between rolls 2, which may be the usual mill rolls, being formed. thereby into a thin sheet 3, the accelerator being added to the batch just before sheeting whereby there will be no substantial procuring in the thin sheet of stock produced. This sheet may be of any desired thickness, it being es-' sential merely that there is no tendency to precure and that in the'subsequent rolling operation, no chamber or cavity be left at the center of the roll. For this purpose sheets of 3 2' of an inch have been successfully used. although such dimensions are not essential. Upon examination of the sheet, it will be found that the fibrous materials are evenly scattered and distributed throughout the sheet but are aligned more or less longitudinally of the sheet, the fibres being illustrated in Figures 2. 4 and 5 at 4.

The sheet ,is then rolled up into a very tight roll transversely of the direction in which it issued from the sheeting rollers without the presence of any crevices totrap air within the mass and the fibres 4: are thus aligned Ion-- gitudinally of the cylinder thus formed.

The roll or cylinder is then cut into secor pellets 8 along transverse lines 6,

tions the mold closed and subjected to vulcanizing temperatures under high pressure exerted upon the mold. It will be noted that by this method the molding pressure is applied in the direction in which the fibres are aligned in the stock, and consequently the fibres are buckled or crushed longitudinally thereof, knitting them together in the vulcanized ball in such a way that the ball will remain of true roundness upon removal from the mold. It has been discovered that if the lass is not subject-ed to pressure in this manner, the vulcanizing pressure serves only temporarily hold the mass in true round form when in the mold, and upon removal there would be an internal readjustment of the fibres, resulting in the ball assuming an untrue shape. The mold may be cut to provide the mesh or dimpled surface standard in all golf balls.

s an example of the subsequent treat- 6 ment, the holds may be subjected. to a ten minute cure at 310 Fahrenheit. By the use of sulphur sufiicient to vulcanize rubber to a comparatively hard state together with powerful accelerators and the higher temperatures fora short period, the finished ball, illustrated at 11 in Figure 7 is cured in a manner which is peculiar to this invention and gives the desirable attributes and properties to the finished ball. It will be found that while the rubber throughout the ball is completely vulcanized, the outer surface of the ball and to a short distance in the rubber is cured to such an extent as to be hard or substantially of the density and non-resilience of hard rubber or gutta percha, while the center of the ball is cured to a less extent, being highly resilient or elastic. This has been attempted to be illustrated in Figure 7 by showing the highly cured, hard outer shell or cover of the ball at 12 and the elastic, resilient interior of the ball which is more resilient at 14, that portion of the ball between the outer shell and the center gradually merging from the hard exterior to the yielding, resilient interior.

The hard exterior of the ball accords the non-cutting surface and gives the desirable click to the ball while the more resilient and less cured interior gives the ball its life and long flight. The fibres give the ball its resistance and assist in its valuable characteristics. The convolutions imparted to the ball during the winding process, which are illustrated in Figure 7, secure the proper balshown in Figure 5, it has been found that a ball of true roundness is secured, the fibres being crushed or buckled endwise by the molding pressure and having no tendency 5 to expand the ballin any direction after the molding pressure is relieved.

What is claimed is: 1. The process of manufacturing golf balls or the like, comprising compounding rubber, 1) fibres, a vulcanizing agent, and an active accelerator, sheeting the said compound, rolling up the sheet so obtained transversely of the direction in which it was sheeted, placing a charge of the rolled material in a mold, and curin under heat and pressure applied longitudmally of the roll of material for a short period at high temperature to obtain a ball, the outer shell of which is hard and highly cured, and the inner portion thereof less highly cured and more resilient.

2. The process of manufacturing golf balls or the like, comprising compounding rubber, i 7

a vulcanizing agent, and an active accelerator, sheeting the said compound, rollin a sheet so obtained into a tight cylinder, p acing a section of the cylinder in a mold, and curing for a periodsuflicient to form a hard rubber outer shell with a softer rubber core. 3. That method of making golf balls or the 80 like which comprises providing a mass of rubber containing fibres aligned more or less in one direction therein, and molding and vulcanizing said mass of rubber by heat and by application of pressure in said direction,

whereby there will be no tendency in the completed ball for the fibres in the ball to read- ]ust themselves upon release of the molding pressure so as to cause the ball to assume an v untrue shape. a 4. A gol ball of molded homo eneous rubber compound throughout, sai compound including fibres and vulcanizing ingredients such as normally. to vulcanize to hard state, the exterior portion of the ball being vulcanized to a comparatively hard state and the central portion of the ball being only partly vulcanized to a comparatively resilient or elastic state. a

5. A golf ball composed entirely of a vulcanized homogeneous composition of rubber including a powerful accelerator and sulphur sufiicient to produce hard rubber, said ball being, vulcanized to a comparatively hard state at the surface and the center portion of the ball being only partly vulcanized'to a comparatively resilient or elastic state.

. JOHN A. CHRISTIE. 

